A pattern begins with two cubes and continues by adding a cube to each side as shown below. Which recursive definition could be used to determine the number of exterior faces in stage n?

Can you simplify 4/7? 24 points will be awarded!

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.

3x + 4y = 5 x- 3y = -7 solve by substitution